This invention relates to a floor tile, in particular a laminate panel, parquet element, veneer floor element, ready-to-lay parquet element or such like, with an edge profile on at least two opposite edges in the form of a modified groove and tongue joint for the purpose of connecting adjacent tiles, with a coincident arrangement consisting of one groove and one tongue on each of at least two edges, of which the tongue on one edge of a first tile and the groove in an associated edge of a second tile rise obliquely upwards from the bottom of the tile.
A floor tile or this type is disclosed in DE 33 43 604 C2. In this prior art tile, the act of connecting two identical tiles results in a xe2x80x9cmodifiedxe2x80x9d groove and tongue joint in that adjacent tiles are held in position by the joint relative to each other in both the vertical and horizontal directions, i.e. they cannot come apart unintentionally. Although this horizontal fixation can also be achieved by glueing together adjacent tiles provided with a simple groove and tongue joint, the glueing process involves considerably more work when laying the flooring, and joints of this kind are often not sufficiently long-lasting.
In practice, there is therefore a preference for the type of edge profiles that guarantee an interlocking connection between adjacent tiles in the horizontal direction as well, without glueing being required.
Interlocking joints of this type are disclosed in the above-mentioned publication as well as in GB 2 256 023 A, WO 98/58142, U.S. Pat. No. 4,426,820, DE-OS 2 238 660, DE 79 28 703 U1 and DE 198 54 475 A1.
In the process of laying the floor tiles described here, the edge profile of each consecutive tile is generally held at an angle and pushed or slotted into the edge profile of a tile that has already been laid, and then lowered into a horizontal position. This ensures that both edge profiles lock into each other. A floor surface that has been laid in this way is removed by executing the steps in reverse order. This type of assembly or disassembly method means that a kind of articulated joint, which allows the tiles to be angled up and down, occurs at the adjacent edges. In prior art solutions, the consequence of this is that the modified groove and tongue joint has low resistance to buckling, and adjacent tiles may bulge or collapse in the vicinity of the joint which separates them. This low resistance to buckling is naturally unacceptable in the context of the glueless laying method that is now preferred today.
This invention is therefore based on the task of providing a floor tile of the above-mentioned type with a modified groove and tongue joint which will lock into place in the horizontal direction as well in the manner defined above, and which also guarantees a joint with high resistance to buckling between adjacent tiles.
In the case of a floor tile of the type mentioned above, this task is solved in that the edge profiles are contrived directly in the support material of the floor tile, in that the groove in the first tile is disposed directly above its tongue, in that the lower wall of this groove falls off towards the back end of the groove by the same degree as the tongue on the first tile rises upwards, in that the upper wall of the groove in the first tile runs essentially parallel to the plane of the tile, and in that the tongue on the second tile matches the shape of the groove in the first tile by having a top surface that runs essentially parallel to the plane of the tile and a bottom surface that falls off towards the end of the tongue.
Since in a certain sense the invention results in a double groove and tongue joint, adjacent tiles are mutually supported in relation to horizontal pull and pressure at several points preferably well spaced apart, so that the joint between adjacent tiles has a correspondingly high resistance to buckling. Even if the tiles are laid without glue in a floating configuration the floor will retain its precisely level position.
With regard to the terminology used here, it should be noted that comments are always made with reference to the tiles in the position in which they are shown in the drawings, which will be explained below. The terms xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d in particular should be understood in this sense. It is also evident, however, that the arrangement could equally well be reversed, i.e. that the positions xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d can be interchanged without departing from the scope of the invention.
Floor tiles of the above-mentioned type are generally made from derived timber products, in particular medium or high density fibreboard, but also from solid wood. Support tiles made from synthetically produced materials or recycled materials such as e.g. polyurethane recycling materials could also be used. The applicability of this invention is not limited with regard to the type of tile material used. In all cases, however, the invention relates to support tiles where the edge profiling is contrived directly in the material of the support tiles. This is not the case with DE 33 43 604 C2 as mentioned at the outset, because in this case the edge profile is formed by an extrusion profile which is connected with the support tile.
The extent of the undercut resulting from the interaction of the tongue on the first tile and the groove in the second tile will also depend in each case on the elasticity of the material. The undercut can be defined by selecting the inclination and the length of the tongue on the first tile. As a general rule, an angle of 15xc2x0 is appropriate.
To facilitate the joining process, the edges at the front end of the tongues and the edges as the entrance to the grooves should preferably be tapered.
The tongue on the second tile is preferably disposed directly above its groove. The tongue on the second tile therefore forms the top limit of the groove in the second tile. The bottom surface of the tongue on the second tile is therefore inclined by the same degree as the tongue on the first tile. Whilst the tongue on the first tile has two essentially parallel top and bottom surfaces inclined upwards at an angle of e.g. 15xc2x0, the lower surface of the tongue on the second tile is inclined downwards towards the free end, as already mentioned, whilst the upper surface is essentially horizontal, i.e. parallel to the tile plane of the tiles to be joined. It is preferable to ensure that the projecting edges on the top and bottom sides of the tongue on the second tile are also tapered. The bottom edge simultaneously forms the top edge of the groove in the second tile.
In the event that the locking effect of the above-mentioned edge joint is insufficient, provision can be made for an additional locking rib with engages with a lokking groove in the other tile. The locking rib can be disposed either on the top or bottom surface of one of the tongues, or, alternatively, on the top or bottom wall of one of the grooves. The locking rib is preferably disposed on the top surface of the tongue on the second tile and the matching locking groove is disposed in the top wall of the groove in the first tile. Basically, however, it is of no importance on which of the tongues the locking rib or locking groove takes effect, or whether this happens on the top or bottom side of the tongue.
If this additional locking means is used, the two tongues can possibly be made shorter, or can be angled to a lesser degree.
The vertical cross-section of the locking rib and locking groove is preferably contrived as a trapezoidal or rounded trapezoidal shape which therefore has sides that slope to a greater or lesser degree. Steep or even vertical sides result in greater rigidity, but render this assembly and disassembly process more difficult.
Another embodiment of the invention is based on a combination of features of the embodiments described above. In this embodiment too, adjacent tiles are held together with a high degree of stability in a level position and prevented from warping or buckling in the vicinity of the seam. The profile in question here is also a double groove and tongue profile with relatively simple, stable profile elements and a relatively low volume of waste in the region of the edge profiles.
A floor tile according to this embodiment in conjunction with the features of the floor tile mentioned above is characterized in that the edge profiles are contrived directly in the support material of the floor tile, in that the tongue on the first tile projects beyond the front end of the first tile, in that the surface on the top side of the tongue on the first tile falls off at an angle into the groove in the first tile, in that the tongue on the second tile has an upwardly projecting rib on its outer edge, and in that a locking groove which corresponds with the rib is provided in the top wall of the groove in the first tile.
With this type of profile adjacent tiles support each other mutually in the upper portion of their front ends, and the tongue on the first tile also rests in the groove in the second tile. This results in two relatively widely spaced support points which securely retain adjacent tiles in a plane-parallel position and prevent them from tilting up or down. Further support is provided in the groove in the first tile, in which the rib on the tongue of the second tile and the locking groove in the groove in the first tile interact.
The advantages achieved are based in particular on the fact that the tongue on the first tile projects beyond its front end and is also inclined upwards at an angle. As a result, this means that the groove in the first tile is at least covered over by the tongue on the first tile and that the locking groove inside the groove in the first tile cannot be milled from outside the groove using a rotating milling cutter. The profile of the invention on the tile edges can therefore only be pre-prepared with the help of milling cutters, with at least partial reworking being required using planing tools which are moved along in the longitudinal direction of the profile edges, or with the profile edges being moved along the planing tools. One advantageous side effect of using such planing tools is that the profiles can be worked with great precision.
This problem also exists with certain feature combinations of the embodiments described above. Any disadvantages arising out of the need for planing also being required in addition to milling are compensated by the fact that the resultant profiles are particularly deep and can be inter-anchored with a high degree of stability.